The present invention relates to a set of electrode positioners, in particular to electrode positioners for skin-contacting surface electrodes used for electrical muscular stimulation in conjunction with a splint.
Electrical stimulation is widely used for pain control (TENS), therapeutic exercise (TESS) and for activating a paralyzed limb (FEES) in order to restore functional activities, e.g., pretension-release of objects. A serious problem encountered by a patient is the need to position the electrodes on his limb each time he sets up the stimulation system. Electrode positioning requires considerable expertise and a great deal of time, especially when the stimulation system is required to activate several muscles in relatively complex movements, and even more so when the muscles are small and the musculature is crowded. For limbs such as the forearm, it is very difficult to position an array of surface electrodes sufficiently accurately to generate a prehension-release pattern in the hand which would facilitate grasp and manipulation of objects and utensils in daily use.
One solution to the above problem has been to arrange the electrodes on the inside surface of a splint, as shown, by way of example, in FIG. 1 of U.S. Pat. No. 5,330,516. During an initial clinical session with the patient, the clinician applies his expertise and arranges the electrode array on the splint. Thereafter, every time the patient uses the device, he places the splint on his arm and the entire electron array locates itself according to the clinician""s arrangement. The problem of this method resides in the fact that even for an experienced clinician, the positioning of electrodes for optimum results is a very time-consuming process, which is also correspondingly wearisome to the patient.
It is thus one of the objects of the present invention to provide a set of electrode positioners that enables a clinician to assess the efficiency of a diversity of electrode locations on the limb of a patient in rapid succession and that, after he has rapidly gone through and tested several or all of the electrode positioners of the set, allows him to attach permanent surface electrodes to the splint, the size, position and orientation of the, electrodes being precisely copied from those of the selected electrode positioners.
It is a further object of the present invention to provide an electrode positioner that will enable the patient himself to activate different muscles of his limb to carry out a variety of functional activities, as well as to exercise his limb using a selection of clinical protocols, choosing different muscles each time.
According to the invention, the above objects are achieved by providing a set of electrode positioners for skin-contacting surface electrodes used for electrical muscular stimulation in conjunction with a splint, said set comprising at least one electrode positioner in the form of a scoop-like structure, the concave surface of which substantially fits a first surface of a patient""s limb; at least one surface electrode of a predetermined size, location and orientation, fixedly attached to said concave surface; terminal means for connecting said at least one electrode to a source of stimulation current, said terminal means being accessible from the rear side of said concave surface, wherein said electrode positioner is configured to be introducible between the surface of said limb and an interior surface of said splint, means being provided to arrest said positioner in a predetermined and reproducible final position relative to said splint.
It will be appreciated that the electrode positioners described below are designed for use with splints intended for the activation, by electrical stimulation, of flexor and extensor muscles, the motor points of which are located in the palmar, respectively, the dorsal, portions of the forearm. Since any useful limb movement requires the action of a flexor as well as an extensor, it is obvious that such a splint must have stimulation electrodes on both the dorsal and palmar sides of the forearm and therefore requires at least two electrode positioners.
It will be further appreciated that a forearm splint was selected by way of example only, splints being feasible also for the lower limbs, the elbow, the shoulder, etc. In such cases, while the mounting and operating principles of the associated electrode positioners remain the same, their specific shape will obviously be dictated by their points of application.